1. Field of the Invention
The present invention relates to an orientation method for a flaky particle and a method for forming a layer of flaky particles, and more particularly to a method of orienting flaky particles so that a flat surface thereof is parallel with a surface of a workpiece and a method of forming a layer on a surface of the workpiece using the flaky particles oriented with the above-mentioned method.
2. Description of the Prior Art
Conventionally, as a method of attaching the flaky particles to a surface of the workpiece in a predetermined orientation, there is known the method of coating a coating material or the like, which is obtained by causing thin-flake-like flaky particles or scale-flake-like flaky particles to be contained in a coat-forming resin. For example, as a method of providing a mirror-like metallic appearance for the workpiece, there is the method of coating a surface of the workpiece with a coat-forming resin containing minute metallic foil which is obtained by grinding a metallic vapor-deposited layer into minute foil pieces (refer to Japanese Patent Application Laid-open No. 2001-226612 (pp. 2-7)).
Coating the surface of the workpiece with the coating material including the coat-forming resin containing the minute metallic foil in this manner allows the metallic foil in the coating material to be arranged in a predetermined orientation in the coat-forming resin, thus making it possible to obtain a uniform, and mirror-like metallic luster surface without remaining particle shapes.
In the method for forming the layer, since the minute metallic foil contained in the coat-forming resin is arranged in a predetermined orientation in the layer as described before, a mirror-like luster surface can be formed.
With the above-mentioned method, however, although the flaky particle is effective in a process intended for a dressing effect which brings the surface of the workpiece to a mirror-like metallic appearance as described above because the flaky particles are attached to the surface of the workpiece in a state of being buried in the coat-forming resin, for example, the processing of attaching the flaky particles composed of a conductive material to a surface of the workpiece, thereby to render it electrically conductive, or the processing of attaching the flaky particles composed of a solid lubricant such as a molybdenum disulfide or graphite to a sliding portion of a mechanical part, being a workpiece, thereby to improve lubricativeness cannot be carried out.
In a case an attempt is made to attach the flaky particles in a state where they are exposed to an outermost surface of the processed product to be coat-treated, a possible method is that a resin as a binder is coated to a processing surface of the workpiece in advance to attach the flaky particles as described above hereto before hardening of this binder. However, when the flaky particles are attached with this method, unless the flaky particles are supplied so that they come into a predetermined orientation, the orientation of the flaky particles is not unified. If an attempt is made to orient the flaky particles, which were attached to the processing surface with its orientation not unified, in a predetermined direction, for example, to orient the flaky particles so that the flat surface thereof is parallel with the surface of the workpiece, the operation of pressing the attached flaky particles in the predetermined direction or the like is required before hardening of the binder after attachment of the flaky particles.
Further, an organic solvent is generally used as a solvent for the coat-forming resin serving as a binder to attach the flaky particles to the workpiece. After coating such a coat-forming resin to the surface of the workpiece, in order to harden the coat-forming resin, it is necessary to dry the resin to vaporize the organic solvent, which may contaminate working and surrounding environments.
If an attempt is made to avoid such contamination, it is necessary to provide equipment or the like to collect the organic solvent that vaporizes during drying and this will force a heavy burden for equipment investment. Besides, because the step of coating the coat-forming resin to the workpiece and drying it after the coating as described above is necessitated, such layer formation requires going through many working processes.
Further, when such a coat-forming resin is used, it takes a long time to form the layer. For this reason, there is a strong demand for the method that allows the flaky particles to be attached to the surface of the workpiece without the aid of such a coat-forming resin.
Thus, the present invention has been developed to eliminate the disadvantages in the prior art and has objects to provide an orientation method for the flaky particle which enables the flaky particles to be oriented in a predetermined direction with respect to a surface of the workpiece in a relatively simple way, and to provide a method of forming a layer using the flaky particles with such orientation.
Another object of the present invention is to provide a method for forming the layer of the flaky particles, which does not require use of the organic solvent or the like and is therefore environment-friendly, by providing a method of attaching the flaky particles, without the aid of the binder or the like, to the surface of the workpiece in a predetermined orientation for layer formation.